1. Field of Invention
This invention pertains to warning lights for emergency vehicles. More particularly, this invention pertains to warning lights that, when actuated, are highly visible and, when not actuated, are not readily discernable as warning lights, thereby providing a stealth mode for the emergency vehicle.
2. Description of the Related Art
Emergency vehicles, when operated during an emergency, must be highly visible to other vehicles and persons in the nearby vicinity of the vehicle. For example, when an emergency vehicle, such as a police cruiser, makes a traffic stop of another vehicle, the emergency vehicle illuminates and displays its warning lights to, first, inform the other vehicle that it must pull over and stop, and, second, to warn other vehicles to stay clear of the emergency vehicle and the stopped vehicle. In this operating mode, the warning lights provide an important notice function, both to the occupants of the stopped vehicle and to others who may encounter the emergency vehicle.
When the warning lights of the emergency are not being operated, the visibility of the warning lights depends upon the purpose of the emergency vehicle. Emergency vehicles that are visibly marked as emergency vehicles, such as marked police cruisers and fire department vehicles, have no need to hide the warning lights when not in use. Other emergency vehicles, such as unmarked police cruisers, have a need for warning lights that are unobtrusive and will not interfere with the activities in which the vehicle may be used. Both types of emergency vehicles have a need for warning lights that are aerodynamically formed so as to reduce wind resistance and wind noise when the vehicle is being operated.
Emergency vehicle warning lights are typically mounted in a manner that allows the lights to be visible on each of the four sides of the vehicle, that is, the front, left and right sides, and the rear of the vehicle. It is common to mount warning lights to the top of a vehicle, such as a police cruiser. Mounted on the roof of the vehicle, the warning lights project a signal 360 degrees around the vehicle.
It is also known to mount warning lights inside the vehicle, for example, inside an unmarked police cruiser. These warning lights either attach to the inside surface of a window or are positioned adjacent the window and are directed outwards. Mounting warning lights in this manner often causes reflections from the windows and stray light that distracts the occupants of the vehicle. In addition to such mounted warning lights often obstructing the view through the window by the vehicle operator, warning lights inside the vehicle often illuminate a portion of the vehicle within the line of sight of the operator, such as the hood or trunk lid, thereby distracting and/or blinding the vehicle occupants.
Examples of this type of warning light mounting include U.S. Pat. No. 4,981,363, issued to Lipman on Jan. 1, 1991, titled “Emergency light/spotlight mechanism for automotive vehicles,” which discloses a “windshield mounted combination emergency light/spotlight mechanism.” U.S. Pat. No. 6,380,865, issued to Pederson on Apr. 30, 2002, titled “Replacement led lamp assembly and modulated power intensity for light source,” discloses a warning signal light 10 attached to the interior of a windshield of an emergency vehicle.
Attempts have been made to incorporate warning lights in equipment that is attached to emergency vehicles. For example, U.S. Pat. No. 5,851,064, issued to Lyons on Dec. 22, 1998, titled “Integrated warning light and rear-view mirror,” discloses a side-view mirror with a forward directed warning light. Depending upon the location of the side-view mirror, the warning light illuminates a portion of the side of the vehicle and that portion of the vehicle is potentially within the line of sight of the vehicle occupants. Another example is U.S. Pat. No. 6,087,932, issued to Belgard on Jul. 11, 2000, titled “Light control system,” which discloses combining warning lights with the operating lights of the vehicle. While this location avoids illuminating a portion of the car, the warning lights are necessarily located close to the ground, which is a good location of operating lights because that location provides good illumination without blinding or distracting other drivers, but that location does not provide sufficient elevation and visibility to meet the notice requirements of warning lights, which need to have sufficient elevation to make the warning lights visible to other drivers.